Cloudflare

In short: Cloudflare is a provider of services that sit between visitors and a website: faster delivery, protection against attacks and DNS.

In more detail: A site’s traffic runs through Cloudflare’s network. This intermediary (reverse proxy) can cache content, fend off attacks and check visitors before they reach your own server.

In Depth

• CDN: content is cached on servers worldwide, visitors load from the nearest location. This lowers latency and the traffic at the origin server.
• DDoS protection: mass requests are filtered, see DDoS.
• WAF: a web application firewall blocks typical attacks on websites.
• DNS: Cloudflare runs authoritative DNS servers and the public resolver 1.1.1.1 (DNS server).
• Turnstile: a bot checker as a replacement for puzzle images (CAPTCHA), see bot protection.
• Note: all data passes through a US provider. This has to be considered for privacy (see GDPR).

See also: bot protection, firewall, proxy